User login
Credit: Caitlin Kleiboer
A candidate malaria vaccine is more effective in children aged 5 months to 17 months than in infants 3 months of age or younger, results of a phase 3 study suggest.
Previous research indicated the vaccine— RTS,S/AS01—may prevent malaria in young children, but its efficacy wanes over time.
Now, researchers have reported that RTS,S/AS01 can sometimes prevent clinical malaria, severe malaria, and malaria hospitalization in children aged 5 to 17 months.
In the younger age group, the vaccine offered some protection against clinical malaria but did not significantly impact the rates of severe malaria or hospitalization.
The RTS,S Clinical Trials Partnership committee reported these findings in PLOS Medicine.
The study was sponsored by GSK Biologicals SA, the developer and manufacturer of RTS,S/AS01, and funded by both GSK Biologicals SA and the PATH Malaria Vaccine Initiative.
The researchers studied 6537 infants aged 6 to 12 weeks and 8923 children aged 5 to 17 months treated at 11 sites in Africa.
Subjects were randomized to receive 3 doses of RTS,S/AS01 or a comparator vaccine—a rabies vaccine (VeroRab) for the children and a meningococcal C conjugate vaccine (Menjugate) for the infants.
The primary outcome, vaccine efficacy (VE), was the reduction in malaria incidence among subjects who received RTS,S/AS01 compared to the incidence among subjects who received a comparator vaccine.
In the 18 months following vaccination, VE was 46% in children aged 5 to 17 months and 27% in infants aged 6 to 12 weeks. In both age groups, VE was highest in the first 6 months after vaccination.
RTS,S/AS01 averted an average of 829 cases of clinical malaria per 1000 children vaccinated (range, 37 to 2365) and 449 cases per 1000 infants (range, -10 to 1402) within 18 months of vaccination.
In children aged 5 to 17 months, VE was 34% for severe malaria, 41% for malaria hospitalization, and 19% for all-cause hospitalization. In the infants, there was no significant protection against severe malaria, malaria hospitalization, or all-cause hospitalization.
Serious adverse events occurred less often in children who received RTS,S/AS01 than in those who received a comparator vaccine—18.6% and 22.7%, respectively. In infants, the rate of serious adverse events was similar between the 2 vaccination groups.
Meningitis was more common in subjects who received RTS,S/AS01 than in those who received a comparator. However, the researchers have not established a causal relationship.
There were 16 cases of meningitis among the 5949 children in the RTS,S/AS01 group, 1 case among the 2974 children in the control group, 9 cases among the 4358 infants in the RTS,S/AS01 group, and 3 cases among the 2179 infants in the control group.
Despite the adverse events associated with RTS,S/AS01 and its decreased efficacy over time, the researchers believe the vaccine shows promise. They noted that, “even at modest levels of VE, the number of malaria cases averted was substantial.”
Now, the group is evaluating whether a booster immunization given 18 months after the primary vaccination can improve the efficacy of RTS,S/AS01.
Results of this study were previously reported at the Multilateral Initiative on Malaria Pan African Conference in October 2013 and published in The New England Journal of Medicine in October 2011 and November 2012. Long-term results of a phase 2 trial of RTS,S/AS01 were published in The New England Journal of Medicine in March 2013. 
Credit: Caitlin Kleiboer
A candidate malaria vaccine is more effective in children aged 5 months to 17 months than in infants 3 months of age or younger, results of a phase 3 study suggest.
Previous research indicated the vaccine— RTS,S/AS01—may prevent malaria in young children, but its efficacy wanes over time.
Now, researchers have reported that RTS,S/AS01 can sometimes prevent clinical malaria, severe malaria, and malaria hospitalization in children aged 5 to 17 months.
In the younger age group, the vaccine offered some protection against clinical malaria but did not significantly impact the rates of severe malaria or hospitalization.
The RTS,S Clinical Trials Partnership committee reported these findings in PLOS Medicine.
The study was sponsored by GSK Biologicals SA, the developer and manufacturer of RTS,S/AS01, and funded by both GSK Biologicals SA and the PATH Malaria Vaccine Initiative.
The researchers studied 6537 infants aged 6 to 12 weeks and 8923 children aged 5 to 17 months treated at 11 sites in Africa.
Subjects were randomized to receive 3 doses of RTS,S/AS01 or a comparator vaccine—a rabies vaccine (VeroRab) for the children and a meningococcal C conjugate vaccine (Menjugate) for the infants.
The primary outcome, vaccine efficacy (VE), was the reduction in malaria incidence among subjects who received RTS,S/AS01 compared to the incidence among subjects who received a comparator vaccine.
In the 18 months following vaccination, VE was 46% in children aged 5 to 17 months and 27% in infants aged 6 to 12 weeks. In both age groups, VE was highest in the first 6 months after vaccination.
RTS,S/AS01 averted an average of 829 cases of clinical malaria per 1000 children vaccinated (range, 37 to 2365) and 449 cases per 1000 infants (range, -10 to 1402) within 18 months of vaccination.
In children aged 5 to 17 months, VE was 34% for severe malaria, 41% for malaria hospitalization, and 19% for all-cause hospitalization. In the infants, there was no significant protection against severe malaria, malaria hospitalization, or all-cause hospitalization.
Serious adverse events occurred less often in children who received RTS,S/AS01 than in those who received a comparator vaccine—18.6% and 22.7%, respectively. In infants, the rate of serious adverse events was similar between the 2 vaccination groups.
Meningitis was more common in subjects who received RTS,S/AS01 than in those who received a comparator. However, the researchers have not established a causal relationship.
There were 16 cases of meningitis among the 5949 children in the RTS,S/AS01 group, 1 case among the 2974 children in the control group, 9 cases among the 4358 infants in the RTS,S/AS01 group, and 3 cases among the 2179 infants in the control group.
Despite the adverse events associated with RTS,S/AS01 and its decreased efficacy over time, the researchers believe the vaccine shows promise. They noted that, “even at modest levels of VE, the number of malaria cases averted was substantial.”
Now, the group is evaluating whether a booster immunization given 18 months after the primary vaccination can improve the efficacy of RTS,S/AS01.
Results of this study were previously reported at the Multilateral Initiative on Malaria Pan African Conference in October 2013 and published in The New England Journal of Medicine in October 2011 and November 2012. Long-term results of a phase 2 trial of RTS,S/AS01 were published in The New England Journal of Medicine in March 2013.
Credit: Caitlin Kleiboer
A candidate malaria vaccine is more effective in children aged 5 months to 17 months than in infants 3 months of age or younger, results of a phase 3 study suggest.
Previous research indicated the vaccine— RTS,S/AS01—may prevent malaria in young children, but its efficacy wanes over time.
Now, researchers have reported that RTS,S/AS01 can sometimes prevent clinical malaria, severe malaria, and malaria hospitalization in children aged 5 to 17 months.
In the younger age group, the vaccine offered some protection against clinical malaria but did not significantly impact the rates of severe malaria or hospitalization.
The RTS,S Clinical Trials Partnership committee reported these findings in PLOS Medicine.
The study was sponsored by GSK Biologicals SA, the developer and manufacturer of RTS,S/AS01, and funded by both GSK Biologicals SA and the PATH Malaria Vaccine Initiative.
The researchers studied 6537 infants aged 6 to 12 weeks and 8923 children aged 5 to 17 months treated at 11 sites in Africa.
Subjects were randomized to receive 3 doses of RTS,S/AS01 or a comparator vaccine—a rabies vaccine (VeroRab) for the children and a meningococcal C conjugate vaccine (Menjugate) for the infants.
The primary outcome, vaccine efficacy (VE), was the reduction in malaria incidence among subjects who received RTS,S/AS01 compared to the incidence among subjects who received a comparator vaccine.
In the 18 months following vaccination, VE was 46% in children aged 5 to 17 months and 27% in infants aged 6 to 12 weeks. In both age groups, VE was highest in the first 6 months after vaccination.
RTS,S/AS01 averted an average of 829 cases of clinical malaria per 1000 children vaccinated (range, 37 to 2365) and 449 cases per 1000 infants (range, -10 to 1402) within 18 months of vaccination.
In children aged 5 to 17 months, VE was 34% for severe malaria, 41% for malaria hospitalization, and 19% for all-cause hospitalization. In the infants, there was no significant protection against severe malaria, malaria hospitalization, or all-cause hospitalization.
Serious adverse events occurred less often in children who received RTS,S/AS01 than in those who received a comparator vaccine—18.6% and 22.7%, respectively. In infants, the rate of serious adverse events was similar between the 2 vaccination groups.
Meningitis was more common in subjects who received RTS,S/AS01 than in those who received a comparator. However, the researchers have not established a causal relationship.
There were 16 cases of meningitis among the 5949 children in the RTS,S/AS01 group, 1 case among the 2974 children in the control group, 9 cases among the 4358 infants in the RTS,S/AS01 group, and 3 cases among the 2179 infants in the control group.
Despite the adverse events associated with RTS,S/AS01 and its decreased efficacy over time, the researchers believe the vaccine shows promise. They noted that, “even at modest levels of VE, the number of malaria cases averted was substantial.”
Now, the group is evaluating whether a booster immunization given 18 months after the primary vaccination can improve the efficacy of RTS,S/AS01.
Results of this study were previously reported at the Multilateral Initiative on Malaria Pan African Conference in October 2013 and published in The New England Journal of Medicine in October 2011 and November 2012. Long-term results of a phase 2 trial of RTS,S/AS01 were published in The New England Journal of Medicine in March 2013.